31 Jul In book: Shafer’s Textbook of Oral Pathology: 7th Edition, Edition: 7 th Edition, Chapter: Routine Histotechniques, Staining and Notes on. 5 Mar Histology refers to the study of microscopic structures in biological material and its ways where individual components are both structurally and. Histology Lab, Biology Spring Dr. Ed Devlin. Webpage for Course: Lab Topic.

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Sections cling to block instead of knife. Tissue specimens received in the surgical pathology laboratory have a request form that lists the patient information and history along with a description of the site of origin. There are five major groups of fixatives, classified according to mechanism of action: Problems in Tissue Processing “Floaters” are small pieces of histotechniquex that appear on a slide that do not belong there–they have floated in during processing.

Picking sections up from water bath. Place in Harris Hematoxylin stain for minutes. What has been added or removed to the slide or micrograph as a result of the technique of preparation? What would this structure look like in another plane of section longitudinal, frontal, transverse, oblique?

This is provided by a metal cation such as iron, aluminum, or tungsten. Formalin and alcohol penetrate the best, and glutaraldehyde the worst.

Since smears are only a cell or so thick, there is no great problem from shrinkage, and since smears are not sectioned, there is no problem from induced brittleness. Correct by first removing paraffin that is present. You will notice that the substage diaphragm will now need to be opened wider to fill the back focal plane of the 40X objective.

Make sketches of typical paper fibers as they appear in air, water and oil.


There are problems with clearing agents. Objective lenses are especially fragile. Automation consists of an instrument that moves the tissues around through the various agents on a preset time scale.

In our procedure small pieces of tissue mm 3 are usually fixed for overnight at room temperature. Although the nucleus and chromosomes are generally rendered easily stainable.

Aldehydes Mercurials Alcohols Oxidizing agents Picrates Aldehydes include formaldehyde formalin and glutaraldehyde.

Specific hazards that you should know about include: The problem arises when, during embedding, not all the tissue is removed from the cassette. Contamination of clearing agents or coverslipping media may also produce a bubbled appearance under the microscope.

How do the cellular and extracellular elements fit into histotechhiques tissue? Lymphocytes can be identified by their large nucleus with masses of chromatin histofechniques.

The persons who do the tissue processing and make the glass microscopic slides are histotechnologists. Initially, the cassettes are placed into a fixative. Lymph node primate sec.

Introductory Histotechniques

Sections are cut then removed from the blade with a small paint brush and placed on a slide covered with a thin layer of albumin and water 4 drops of water. This work will be done independently with the help of the instructor.

Ed Devlin Webpage for Course: Though alcohols such as ethanol make excellent fixatives for cytologic smears, they tend to make tissue sections brittle, resulting in microtome sectioning artefacts with chattering and a “venetian blind” appearance. Alcohols, specifically histitechniques, are used primarily for cytologic smears. Artefacts in Histologic Sections A number of artefacts that appear in stained slides may result from improper fixation, from the type of fixative, from poor dehydration and paraffin infiltration, improper reagents, and histotecnhiques microtome sectioning.

This calcium must be removed prior to embedding to allow sectioning. The routine stain is that of hematoxylin and eosion H and E. The purpose of the field diaphragm is to reduce glare.



A buffer prevents acidity that would promote autolysis and cause precipitation of formol-heme pigment in the tissues. There are common usages for fixatives in the pathology laboratory based upon the nature of the fixatives, the type of tissue, and the histologic details to be demonstrated.

If hiistotechniques have a slide in your set that is from another box, see your lab instructor. Fixation – types of fixatives The purpose of fixation is to preserve tissues permanently in as life-like a state as possible.

Esophagus and stomach l. The staining process makes use of a variety of dyes that have been chosen for their ability to stain various hisrotechniques components of tissue. We will use one of the common hietotechniques procedures, hematoxylin and eosin or the H and E staining procedure.


Eosin is much more forgiving than hematoxylin and is less of a problem in the lab. There is no ideal fixative suitable for all tissues. Penetration of nistotechniques depends upon histotchniques diffusability of each individual fixative, which is a constant.

Once the tissues have been embedded, they must be cut into sections that can be placed on a slide. Since they contain mercury, they must be disposed of carefully. Formulate hypotheses hitotechniques the tissue and test them. Never use the substage diaphragm to control the intensity of light. The stained slide is taken through a series of alcohol solutions to remove the water, then through clearing agents to a point at which a permanent resinous substance beneath the glass coverslip, or a plastic film, can be placed over the section.

Concepts covered during the lectures include:.